1. Field of Invention
This invention relates to a grommet. In particular, this invention relates to a grommet that engages around a wire harness to be mounted on an automobile, and is mounted in a through hole of an automobile body panel, and improves protection of the wire harness at a position where the wire harness passes through the hole, as well as improving waterproofness and dustproofness.
2. Description of Related Art
Conventionally, a grommet engages around a wire harness to be mounted to extend from an engine compartment to a passenger compartment of an automobile, and the grommet is mounted in a though hole in an automobile body panel that divides the engine compartment from the passenger compartment. Thus, the wire harness passing through the through hole is protected, and intrusion of water, dust and sound from the engine compartment side to the passenger compartment side is prevented.
As the grommet described above, a so-called one motion grommet is provided. When the one motion grommet is simply pressed into the through hole in the automobile body panel from one side to the other, an automobile body engagement recess provided on an outer peripheral surface of the grommet engages with an edge of the through hole.
As shown in FIG. 21, the above-described grommet 1 is provided with a small-diameter cylindrical portion 2, and a tapered portion 3 which extends from an end of the small-diameter portion 2. The tapered portion 3 is provided with an automobile body engagement recess 4 around a larger diameter end. Both side walls facing each other across a groove 4a of the automobile body engagement recess 4 include a vertical wall 4b at the larger diameter side and an inclined wall 4c at a smaller diameter side. A wire harness W/H (FIG. 22) is inserted into a hollow portion extending from the small-diameter cylindrical portion 2 to the tapered portion 3 of the above-described grommet 1, and the grommet 1 is fixed with the wire harness W/H using a tape T at an end of the small-diameter cylindrical portion.
As shown in FIG. 22, during a mounting operation of the grommet 1 into the through hole H of the automobile body panel P, the grommet 1 is inserted into the through hole H from the small-diameter cylindrical portion 2, and the inclined wall 4c is pressed inwardly and deformed to pass through the through hole 4. Then, the inclined wall 4c, which recovers its original shape after passing through the through hole H, and the vertical wall 4b are tightly pressed into contact with both surfaces of the automobile panel P, respectively. Thus, the automobile body engagement recess 4 of the grommet 1 engages with the through hole H of the automobile body panel P.
In addition, as shown in FIG. 23, in the above-described one motion grommet, since the diameter is smoothly enlarged in a direction from the small-diameter cylindrical portion 2, which is an insertion side, to the inclined wall 4c, no tactile sensation can be felt and it is difficult for the operator to recognize the position from which the operator must forcefully press the grommet. In other words, when the inclined wall 4c is bent in the diameter-reducing direction to pass through the through hole, if a strong pressing force is applied without stopping when a large pressing force is required, the grommet can be inserted into the through hole efficiently. However, the operator cannot recognize the position where the force to be applied without stopping is required, and thus may apply an excessive force from the beginning, and an extra force might be required in the operation.
However, as shown in FIGS. 24(A) and 24(B), when the one motion grommet 1 is inserted into the through hole H so as to be inclined, one side of the tapered portion 3 is pressed excessively, and thus, an outer peripheral surface of a thin portion of the tapered portion 3, extending to the inclined wall 4c of the automobile body engagement recess 4, is deformed inwardly. The inclined wall 4c, which must be bend inwardly, is bent and warped (flipped over) outwardly, and the inclined wall 4c touches the automobile body panel P. Thus, the grommet is prevented from passing through the through hole H.
When the grommet 1 is inserted straight so that the center axis of the grommet 1 is aligned with the center of the through hole H, the above-described problem does not occur. However, during the insertion operation of the grommet 1 into the through hole, it is sometimes difficult to insert the grommet 1 into the through hole straight, because of the restriction on a space. Thus, in many cases, the grommet is inserted in an inclining posture.
Further, if the tapered portion of the grommet 1 is thick so as to be incapable of being bent, the above-described problem is resolved to a certain extent. However, in that case, an insertion force required to insert the grommet into the through hole become larger.
On the other hand, if the tapered portion is too thin, since the stiffness of the tapered portion becomes small, and thus, the tapered portion becomes easily extended while the inserting operation is performed, an insertion stroke becomes long.
Accordingly, the present invention is provided in view of the above-described problems, and an objective of the present invention is to prevent the insertion force from being too large, and to enable a grommet to be mounted into a through hole of an automobile panel, even if the grommet is inserted in an inclining posture, and to reduce extension of the grommet at the time of insertion into the through hole and thus, to shorten the insertion stroke.
Another objective of the present invention is to remove useless consumption of energy of an operation by providing a reasonable point at the position where a force must be applied without stopping to press the grommet into the through hole, during the inserting operation of the grommet into the through hole of the automobile body panel.
To achieve the above and/or other goals, the present invention provides a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel. The grommet includes a tubular portion, a tapered portion extending from one end of the tubular portion, a first wall provided around the tapered portion at a large diameter end, a second wall provided around the tapered portion and located at a small diameter side of the first wall and a plurality of projecting strip portions provided on an outer peripheral surface of the tapered portion. The tapered portion includes an automobile body engagement recess, formed by the first and second walls, provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The second wall faces the first wall across the automobile body engagement recess. The plurality of projecting strip portions extend in an axial direction of the tapered portion and are spaced from each other in a circumferential direction. The plurality of the projecting strip portions are arranged close to each other at a small diameter side of the tapered portion and are radially spread toward the large diameter end. The grommet further includes at least one sunken portion that is defined as the outer peripheral surface of the tapered portion between adjacent projecting strip portions. The sunken portion includes a groove extending in the axial direction. The second (inclined) wall is bent inwardly to enable the grommet to pass through the through hole, when the grommet is being mounted in the through hole.
Preferably, the groove extends between a periphery of a small diameter end, connecting to the tubular portion, and a periphery of an end of the second wall.
As described above, if a groove is provided extending in the axial direction between a periphery of a small diameter end, connecting to the tubular portion, and a periphery of the automobile body engagement recess, since the portion of the groove is thinned, the grommet becomes easy to bend. Accordingly, even if the grommet is inserted in an inclining posture and is hooked by the inner peripheral surface of the through hole, the grommet is bent and the inserting posture is easily corrected.
When the outer projecting strip portions are provided on the outer peripheral surface of the grommet, and when the grommet is inserted in an inclining posture, first, the outer projecting strip portions touch the inner peripheral surface of the through hole. Accordingly, the operator can recognize the inclined insertion, and reinsert the grommet in a straight manner.
Further, if the outer projecting strip portions are provided on the outer peripheral surface of the tapered portion, when the grommet is inserted in an inclining posture, the phenomenon in which the thin tapered portion extending to the inclined wall of the automobile body engagement recess is warped outwardly (flipped over) at the side contacting the inner peripheral surface of the through hole, does not occur. Accordingly, the problem that occurred at the time of inclined insertion in the conventional grommet can be obviated.
Thus, if the projecting strip portions are arranged close to each other at the small diameter side, it is favorable for the correction of the direction at the time of inclined insertion. When the grommet is inserted in a straight manner, even if the projecting strip portions are arranged close to each other, since they do not contact the inner peripheral surface of the through hole, the inserting force does not increase.
On the other hand, since the area of the thin sunken portion becomes larger toward the large diameter side, the grommet is easily bent in a diameter reducing direction, and the inserting force can be reduced.
Since the groove is provided in the sunken portion, the grommet is easily bent inwardly about the center groove, when the outer surface of the projecting strip portions contacts the inner peripheral surface of the through hole.
The groove can be a single center groove provided at the center of the sunken portion, or can be two side grooves provided along the proximal portions of the projecting strip portions. It is possible to provide both the center groove and the two side grooves. In this case, preferably, both side grooves extend to the end of the inclined (second) wall and the center groove extends only to the periphery of the end of the inclined (second) wall, i.e., is shorter than the side grooves.
Further, a V-shaped groove that connects the side grooves to the end of the center groove can also be provided.
As described above, if the single center groove is provided at the center of the triangle sunken portion, the grommet is easily bent about the center groove. Further, if the groove is provided along the proximal portion of the projecting strip portion, the proximal portion of the projecting strip portion is easily bent. Further, if both the single center groove and the two side grooves along the proximal portions are provided, the ease of bending is doubled. Furthermore, since the area of the sunken portion becomes larger toward the large diameter side, if the V-shaped groove, connecting the end of the center groove to both side grooves, is provided, the groove guides the sunken portion in the direction in which the sunken portion is folded, and the diameter of the tapered portion can be naturally reduced.
The projection amount of the above-described projecting strip portions is changed at a contact point where the projecting strip portions contact an inner peripheral surface of the through hole during the insertion into the through hole, so that the projection amount between the contact point and a large diameter side end of the projecting strip portions becomes small.
The portion where the projection amount becomes small, has a shape which the outer surface of the projecting strip portion is bent to have different inclination angle, or a curved (arc) shape.
Accordingly, when the grommet is inserted in the through hole of the automobile body panel, since the projection amount of the projecting strip portions changes, the tactile sensation is generated when the contact point reaches the panel position. From this contact point, the inclined wall must be pressed to be bend inwardly. Thus, from the time when the tactile sensation is generated, if the operator increases the force to press the grommet into the through hole without stopping when the tactile sensation is generated, the inserting operation of the grommet into the through hole becomes efficient. In addition, since the projection amount of the projecting strip portions becomes small from the contact point, the inserting force can be reduced.
Further, an opening is provided in the outer peripheral surface of the tapered portion and a cable insertion cylindrical portion, connecting to the opening, is provided on the interior of the tapered portion and extends outwardly from a thin end face portion. The opening is located in the sunken portion between the projecting strip portions.
As described above, if the cable insertion cylindrical portion is provided, when there are optional parts, a cable to connect to the optional parts is inserted into the cable insertion cylindrical portion, and can be inserted into the through hole of the automobile body panel. Thus, the grommet becomes more versatile.
An extending end of the cable insertion cylindrical portion is closed, and, at the time of use, the end is cut or broken off to provide an opening so that a cable can be inserted into therein.
Further, since the opening of the cable insertion cylindrical portion is provided in the sunken portion of the tapered portion, the sunken portion can be easily deformed, and thus, the inserting force at the time of insertion operation into the through hole can be reduced.
According to the another aspect of the present invention, a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel is provided. The grommet includes a tubular portion, a tapered portion extending from one end of the tubular portion, a first wall provided around the tapered portion at a large diameter end, and a second wall provided around the tapered portion and located at a small diameter side of the first wall, and a plurality of projecting strip portions provided on an outer peripheral surface of the tapered portion. The tapered portion includes an automobile body engagement recess, formed by the first and second walls, provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The second wall faces the first wall across the automobile body engagement recess at a small diameter side of the first wall. The plurality of projecting strip portions extend in an axial direction of the tapered portion and are spaced from each other in a circumferential direction. The tapered portion further includes a recess in an inner peripheral surface of the tapered portion, the recess being located at an inner surface side of the second wall.
Further, since the recess is provided in the inner surface of the tapered portion, the inclined (second) wall is easily bent in a diameter reducing direction. As a result, the inserting force of the grommet can be reduced. Preferably, the recess is inclined toward the inner side of the bottom surface of the groove. According to this construction, the inclined (second) wall can be bent more easily.
In another aspect of the present invention, a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel is provided. The grommet includes a tubular portion, a tapered portion extending from one end of the tubular portion, a first wall provided around the tapered portion at a large diameter end, and a second wall provided around the tapered portion and located at a small diameter side of the first wall. The tapered portion includes an automobile body engagement recess, formed by the first and second walls, provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The second wall faces the first wall across the automobile body engagement recess. The tapered portion further including a V-shape recess in an inner peripheral surface of the tapered portion at an inner surface side of the second wall. The V-shape recess has a shape substantially similar to an outline of the second wall so as to make the second wall thin.
As described above, if the V-shaped recess, which has a similar shape to the outline of the inclined (second) wall whose cross-section has a triangular shape is provided, the entire inclined (second) wall can be thinned. As a result, at the time of insertion into the through hole of the panel, the inclined (second) wall is easily bent inwardly and the inserting force can be reduced.
In a further aspect of the present invention, a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel is provided. The grommet includes a tubular portion, a tapered portion extending from one end of the tubular portion, a first wall provided around the tapered portion at a large diameter end, and a second wall provided around the tapered portion and located at a small diameter side of the first wall, a plurality of projecting strip portions provided on an outer peripheral surface of the tapered portion, a thin end face portion provided at an end of the large diameter side of the tapered portion and a second tubular portion extending outwardly from the center of the end face portion. The tapered portion includes an automobile body engagement recess, formed by the first and second walls, provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The second wall faces the first wall across the automobile body engagement recess at a small diameter side of the first wall. The plurality of projecting strip portions extends in an axial direction of the tapered portion and are spaced from each other in a circumferential direction. The second tubular portion includes a pair of slits facing each other so that the second general cylindrical portion is divided into two generally half-cylindrical portions.
According to the above-described construction, the projecting strip portions provided on the outer surface of the tapered portion provides the above-described function. In addition, the second tubular portion is provided and the second tubular portion is divided into two pieces. As a result, after the grommet is mounted on the panel, it is difficult for the grommet to become separated from the panel.
In other words, the wire harness is inserted into the second generally (small diameter) cylindrical portion through the hollow portion (interior) of the tapered portion, and is fixed to the second tubular portion by taping.
Thus, if the wire harness is fixed to the second small diameter (generally) cylindrical portion located at the side opposing to the pressing (inserting) side, when a force tending to cause separation is applied to the first small diameter (generally) cylindrical portion of the grommet, since the wire harness is fixed to the second small diameter (generally) cylindrical portion, a resisting force against the direction of the separation is generated. Thus, the grommet is prevented from being separated from the panel.
Further, if a slit is provided in the second small diameter (generally) cylindrical portion to divide the second small diameter (generally) cylindrical portion into two pieces, the insertion of the wire harness becomes easy.
According to a further aspect of the present invention, a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel is provided. The grommet includes a tubular portion, a tapered portion extending from one end of the tubular portion, a first wall provided around the tapered portion at a large diameter end, a second wall provided around the tapered portion and located at a small diameter side of the first wall, a thin end face portion provided at an end of the large diameter side of the tapered portion and a second tubular portion extending outwardly from the center of the end face portion. The tapered portion includes an automobile body engagement recess, formed by the first and second walls, provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The second wall faces the first wall across the automobile body engagement recess at a small diameter side of the first wall. The second tubular portion includes a pair of slits facing each other so that the second general cylindrical portion is divided into two generally half-cylindrical portions. The tapered portion further includes a recess in an inner peripheral surface of the tapered portion, the recess located at an inner surface side of the second wall.
In the grommet having the above-described construction, when the grommet is inserted into the through hole of the panel, the recess provided in the inner surface of the inclined (second) wall (tapered portion) realizes a small inserting force, and prevents the grommet from being separated from the panel, after the grommet is once mounted on the panel.
Preferably, the plurality of projecting strip portions extend between a small diameter end, connecting to the tubular portion, and an edge of the second wall. In addition, a projection amount of the plurality of projecting strip portions is changed at a contact point so that a first projection amount between the contact point and the edge of the second wall is smaller than a second projection amount between the contact point and a small diameter side end of the plurality of projecting strip portions. The contact point is located substantially at a position where an outer surface of the plurality of projecting strip portions first contacts an inner peripheral surface of the through hole when the grommet is being inserted into the through hole from the end of the grommet having the tubular portion.
The outer surface of the projecting strip portions may be bent at the contact point as a border so as to have different inclination angle. Instead, the outer surface may have a curved or arc shape from the contact point to the end of the inclined (second) wall.
Preferably, each of the plurality of projecting strip portions has a constant width in the circumferential direction along the axial direction, and the plurality of the projecting strip portions are arranged close to each other at a small diameter side of the tapered portion and are radially spread toward a large diameter side so as to define at least one sunken portion, which is in the outer peripheral surface of the tapered portion between adjacent projecting strip portions. The sunken portion includes a groove extending the axial direction.
In a still further aspect of the present invention, a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel is provided. The grommet includes a tubular portion, a tapered portion extending from one end of the tubular portion, a first wall provided around the tapered portion at a large diameter end, and a second wall provided around the tapered portion and located at a small diameter side of the first wall, and a plurality of projecting strip portions provided on an outer peripheral surface of the tapered portion. The tapered portion includes an automobile body engagement recess, formed by the first and second walls, provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The second wall faces the first wall across the automobile body engagement recess at a small diameter side of the first wall. The plurality of projecting strip portions extend in an axial direction of the tapered portion and are spaced from each other in a circumferential direction. The tapered portion further includes a recess in an inner peripheral surface of the tapered portion, the recess being located at an inner surface side of the second wall. The grommet further includes at least one small stepped portion provided on a sunken portion of the outer peripheral surface of the tapered portion between adjacent outer projecting strip portions, the small stepped portion projecting from an edge of the second wall toward the tubular portion.
Similar to the conventional grommet, the grommet of the present invention is made of any suitable elastic material, such as an elastic or an elastomer, and has predetermined flexibility.
The end of small stepped portion for tactile sensation is raised in a direction substantially perpendicular to the outer peripheral surface of the tapered portion. Accordingly, when the grommet is being inserted into the through hole of the automobile body, the small stepped portion touches the periphery of the through hole and the operator feels tactile sensation.
When the operator feels the tactile sensation and concentrates his strength from the position to press the grommet without stopping, the operator can insert the grommet into the through hole without extra energy.
Preferably, a projection amount of the plurality of outer projecting strip portions changes in the axial direction, and the outer surface of the outer projecting strip portions has a straight line when the outer surface of the plurality of strip portions has a height from an axis of the grommet same as a height of the edge of the second wall. In addition, the small stepped portion extends linearly straight from the edge of the second wall to the position where the outer surface of the plurality of projecting strip portions changes to the straight line.
Thus, the small stepped portion projecting from the sunken portion does not exceed the outer projecting strip portions. Accordingly, the small stepped portion is not hooked by the periphery of the through hole of the automobile body and does not interfere the inserting operation. Further, if the portion for tactile sensation (small stepped portion) is provided on the outer projecting strip portion, the thickened portion by the small stepped portion becomes difficult to bend. However, since the small stepped portion for tactile sensation is provided on the sunken portion, the small stepped portion can be bent relatively easily and does not impede the reduction of the inserting force of the grommet.
Preferably, the outer peripheral surface of the tapered portion defining the sunken portion between the adjacent outer projecting strip portions includes a center groove at a center of the sunken portion in the circumferential direction and two outer side grooves along proximal portions of the plurality of outer projecting strip portions. The two outer side grooves extend to a periphery of the edge of the second wall. The center groove does not extend to the periphery of the edge of the second wall. The small stepped portion is provided on an extension of an end of the center groove. The two outer side grooves are located at both sides of the small stepped portion.
As described above, if the groove is provided in the sunken portion between the outer projecting strip portions, the sunken portion is bent extremely easily. Thus, while the stiffness is improved by providing the projecting strip portions of the tapered portion, the tapered portion can be bent smoothly in the diameter reducing direction at the time of insertion of the grommet into the through hole. Thus, the inserting force can be reduced.
In addition, if the grooves are located at both sides of the small diameter portion for tactile sensation, the small stepped portion becomes bent easily. Accordingly, the small stepped portion is bent easily by the pressing force and passes through the though hole of the automobile body.
In addition, the inner projecting strip portions can be provided on the inner peripheral surface of the tapered portion, so that the inner projecting strip portions oppose the outer projecting strip portions. Thus, if both the inner and outer projecting strip portions are provided on the thin tapered portion, the tapered portion is reinforced. Accordingly, when the grommet is inserted in an inclining posture, the phenomenon in which the thin tapered portion extending to the inclined wall of the automobile body engagement recess is warped outwardly (flipped over) at the side contacting the inner peripheral surface of the through hole, does not occur. Accordingly, the problem that occurred at the time of inclined insertion in the conventional grommet can be resolved. In addition, by increasing the stiffness of the tapered portion to suppress the extension of the tapered portion, the inserting stroke into the through hole of the automobile body can be shortened.
In particular, even if the thickness of the outer projecting strip portions provided on the outer peripheral surface of the tapered portion is small, since the inner projecting strip portions are provided on the inner peripheral surface of the tapered portion, opposing the outer projecting strip portions, the thickness of a sum of the outer projecting strip portion and the inner projecting strip portion becomes large, and a required reinforcement can be achieved. Accordingly, the thickness of the outer projecting strip portions provided on the outer peripheral surface of the tapered portion can be small, and thus, the outline of the entire grommet is prevented from being larger.